Spring construction



` Sept. 2, 1941; R. `Y. MILLAR 2,254,379

SPRING CONSTRUCTION Filed Sept. 25, 1939 2 Sheets-Shee'kI 1 INVENTOR. R THERFORD YMILLAR BY IL" l ATTORNEYS FIGB nnlualllilll RPM Sept. 2, 1941. R Y NULLAR Y 2,254,379

SPRING CONSTRUCTION Filed Sept. 25, 1939 2 Sheets-Sher#l 2 INVENTOR. BUTHER FORD Y.MILLAR Y www,

ATTORNEYS Patented Sept. 2, 1941 SPRING CONSTRUCTION Rutherford Y. Millar, Oakland, Calif., assignor to National Automotive Fibres, Inc.,

Detroit,

Mich., a corporation of Delaware Application September 25, 1939, Serial No. 296,475

8 Claims.

The present invention relates to spring construction and more particularly to a spring construction embodying leaf springs and characterized by relatively small thickness.

It is an object of the present invention to provide a spring construction having a plurality of outwardly bowed leaf springs in combination with other resilient means tending to resist flexing of said leaf springs in a direction to reduce the amount of bow.

A further object of the present invention is to provide outwardly bowed leaf springs having a coil spring associated at each end thereof, said coil spring adapted to urge the ends of said leaf springs toward each other.

It is a further object of the present invention to provide a spring construction having a plurality of outwardly bowed leaf springs in combination with second leaf springs engaging the mid portions of the first leaf springs in a manner to resist inward flexing thereof.

It is a further object of the present invention to provide a spring construction having a plurality of outwardly bowed leaf springs in combination with means interconnecting the ends of each of said leaf springs to the opposite ends of the adjacent leaf springs.

It is a further object of the present invention to provide a spring construction comprising a plurality of outwardly bowed leaf springs, each of said springs being formed throughout its length to provide a plurality of relatively. short sinuous curves.

Other objects of the invention will be apparent as the description proceeds, and when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a transverse section through a seat back or cushion embodying my invention;

Figure 2 is a section on the line 2-2, Figure 1;

Figure 3 is a detail sectional view showing means for adjusting the tension of the coil springs;

Figure 4 is a diagrammatic view illustrating the tension adjusting means shown in Figure 3; and

Figure 5 is an elevation of a somewhat modied form of leaf spring.

Referring first to Figures l and 2 I have illustrated at I a frame, herein illustrated as being formed of sheet metal having its opposite sides bent to form end iianges I I and inwardly extending flanges I2. It will be noted that the frame Ill, together with the flanges II and I2 denne inwardly open channels. rIhe spring construction which forms the basis of the present application is carried by the frame IIl and is adapted to have suitable upholstery material secured thereover. In Figure 1 the upholstery material is illustrated as comprising an inner pad I3 which may be formed of sisal, jute or the like, and. an outer pad I4 which is preferably of some soft fibrous material, such for example as cotton. A trim fabric I overlies the cotton and provides the wearing surface. The frame III is covered at its back with a panel board I6 which may if desired be covered with a suitable trim fabric I1. The fabrics I5 and I'I may, if desired be provided with suitable decoration and may be formed as by sewing or otherwise to provide pleats.

The spring construction comprises essentially a plurality of leaf springs 30 having their ends bent to provide ears 3|, together with coil compression springs 50 and intermediate secondary leaf springs l0.

In the channels provided by the frame I0 and the iianges II and I2 are provided a plurality of spring retaining cups I8, which may be soldered, welded or otherwise secured therein. The cups I8, together with the flanges II and I2 provide spring housings which are completely enclosed except for openings indicated at I9. More specifically the cups I8 are provided with stops 20 for a purpose subsequently to be described. The coil springs 50 are received within the cups I8 and are adapted to engage the ears 3l of the leaf springs 3G. As clearly shown in Figure 1, the ends of the leaf springs 30 extend through the opening I9 in the cups I8. As will be evident the coil springs 50 urgethe ends of the leaf springs 3U inwardly in a manner to resist flexing thereof.

Auxiliary leaf springs 10 are provided which are bowed in the same direction as the leaf springs 30, but on a shorter radius. The leaf springs 'I0 engage and are preferably secured to the leaf springs adjacent the mid portion thereof. The ends of the auxiliary springs 'IIJ are bent as indicated at II to provide rounded bearing elements. Wear plates I2 are secured to the inner surface of the frame I0, and the ends 1I of the auxiliary springs III are in slidable contact with the wear plates I2. As will be evident, auxiliary, springs 'III further tend to oppose inward flexing of the leaf springs 30. By properly selecting the effectiveness of the springs SII, and 10, it is possible to control the action or ride of the springs.

As best seen in Figure 2, the leaf springs 30 are interconnected by tension members, such as wires 32. As will be noted, the wires 32 are inherent resilience of the leaf spring, the resilience of the corresponding auxiliary spring lll,Y

the force of the compression springs 50, andthe effect of wires 32. n

As previously stated, the eectiveness of the spring unit as a whole may be controlled by selecting springs 30, 50 and 10 having desired degrees of individual effectiveness. In some cases, however, it is desirable to vary the effectiveness of the spring unit as a whole, and for this purpose I provide the structure. illustrated in Figures 3 and 4. In these figures I have shown the coil springs 50 as receiving the cup I8, which in turn is secured in the channel' formed by the frame I and the flanges l-I and I2. In this instance, however, the coil springsV l] instead of abutting directly against the flanges H, as illustrated in Figure 2, is provided with a floating plate 2l whichV extends along the channel previouslyv referred to. It will be understood, of course, that the cup YIB Vis apertured to permit movement of the floating plate 2l.

A shaft 22 is carried by the frame by suitable means (not shown), and secured at spaced points along the shaft 22 are a plurality of cams 23. The cams 23 may take the formV of eccentrics on the shaft 22 and as will be evident, rotation of the shaft 22 will move the floating plate 2| inwardly or outwardly, thus varying the compression and effectiveness of the spring 58. I have illustrated means for manually adjusting the amount of rotation of shaft 22 as comprising a gear 24, keyed or otherwise secured to the shaft 22, in combination with a worm 25 carried by a shaft 26 which spans the channel formed by the frame I0 and flanges Il and` l2. The shaft 26 is provided with a manual adjustment'knob 21. It has been found that adjustment of the tension of the springs 50 has a marked effect on the action of the spring unit as a whole.

While in the foregoing description I have illustrated the leaf springs 30 as being of uniform curvature, in some instances I prefer to employ a leaf spring as illustrated in Figure 5. InV

this case the leaf spring 40 is initially formed with a plurality of short curves, as illustrated, so as to have a sinuously curved shape, as indicated in Figure 5. The ends of the spring 4D are bent to provide ears 4l, similar in all respects to the ears 3| ofthe leaf springs 38 illustrated in Figure l. Except for the initial formation into the sinuous shape, the spring 40 is identical with spring 30 and -cooperates with the other elements of my combinaiton in identical manner. The term "sinuously curved is intended to define a leaf spring having a plurality of shallow corrugations, each of which has a greater dimension longitudinally of the leaf spring than its depth, as clearly shown in Figure 5.

While I have illustrated and described but one main modification of my invention, it will be apparent to those skilled in the art that various additions, modifications, omissions, combinations and substitutions may be made which will be within the spirit and scope of my invention as dened by the appended claims.

What I claim as my invention is:

1. A spring construction comprising a frame having opposing channels along opposite sides, a plurality of outwardly bowed leaf springs having their ends slidable in said channels, coll springs in said channels engaging the ends of said leaf springs and urging them toward each other, spring retaining cups in said channels for receiving said coil springs, said cups providing stops for limiting inward movement of the ends of said leaf springs.

2. A spring construction comprising a backing frame, a plurality of leaf springs mounted on said frame and bowed away therefrom, resilient means operatively associated with said leaf springs and opposing flexing of said springs toward said frame, and tie means interconnecting adjacent leaf springs for distributing load, said tie means comprising tension members interconnecting the opposite ends ofadjacent members.

3. A spring construction comprising a backing frame, a plurality of leaf springs mounted onl said frame and bowed away therefrom, resilient means operatively associated with said leaf springs and opposing flexing of said springs toward said frame, and tie means interconnecting adjacent leaf springs for distributing load, said tiev means comprising tension members connecting one endof eachY intermediate leaf spring to the opposite end of each adjacent leaf spring.

4. A spring construction comprising a generally flat metal frame having its opposite edges bent to form opposed inwardly opening channels, a plurality of cups in said channels, coil compression springs in said cups,- said cups having substantially closed inner ends provided with elongated openings, a plurality of substantially parallel outwardly bowed leaf springs extending across said frame, the ends of said springs extending through said openings into said' cups, and into engagement withsaid coil springs, the ends of said leaf springs having abutments thereon engaging the closed inner ends of said' cups to limit inward movement of said ends, a second leaf spring associated with each of said first leafsprings, said leaf springs engaging centrally of each other, said second' leaf springs being bowedsimilarly to Vthe bowing of said rst leaf springs but on a shorter radius, the ends of said second leaf springs being slidably engaged on said frame, and tie wires connecting each end of said rst leaf springs with the opposite end of each adjacent one of said first leaf springs.

5. A spring construction comprising abacklng frame, a plurality of leaf springs mounted on said frame and bowed Aaway therefrom, resilient means operatively associated with said leaf springs. and opposing flexing of said springs toward said frame,V said means comprising coil springs engaging the ends of said leaf springs,

an adjustable abutment engaging all of said coil springs along one side of said frame, and cam means for adjusting said abutment to vary the effectiveness of all of said coil springs.

6. A spring construction comprising a backing frame, a plurality of leafsprings mounted on said frame and bowed away therefrom, resilient means operatively associated with said leaf springs and opposing flexing of said springs toward said frame, said means comprising coil V springs engaging the ends of said leaf` springs,

an adjustable abutment engaging all of said ycoil 8. A spring construction comprising a backing frame, a plurality of generally parallel leaf springs carried by said frame, said springs being bowed away from said frame and having their ends s-lidable thereon, guides on said frame for guiding sliding movement of the ends of said leaf springs, abutment means limiting sliding movement of the ends of said leaf springs, and tie means interconnecting adjacent leaf springs for distributing load, said tie means comprising tension members interconnecting the opposite ends of adjacent leaf springs.

RUTHERFORD Y. MILLAR. 

